If then we had merely to account for cases in which prayer does not happen to have been recorded as a constituent part of the rite of worship, we should not be warranted in inferring that prayer was really absent. The presumption would rather be that either the records are faulty, or that prayer, even though not uttered in word, yet played its part. The ground for the presumption is found in the nature of the occasions on which the gods are approached in the lower stages of religion. Those occasions are either exceptional or regularly recurring. The exceptional occasions are those on which the community is threatened, or afflicted, with calamity; and on such occasions, whether spoken words of prayer happen to have been recorded by our informants, or not, it is beyond doubt that the purpose of the community is to escape the calamity, and that the attitude of mind in which the god is approached is one of supplication or prayer. The regularly recurring occasions are those of seed-time and harvest, or first-fruits. The ceremonies at seed-time obviously admit of the presumption, even if there be no spoken prayers to prove it, that they too have a petitionary purpose; while the recorded instances of the prayers put up at harvest time, and on the occasion of the offering of first-fruits, suffice to show that thanksgiving is made along with prayers for continued prosperity. It is however not merely on the ground of the absence of recorded prayers that it is maintained that there was a stage in the evolution of religion when prayer was unpractised and unknown. It is the presence and the use of spells which is supposed to show that there may have been a time when prayer was as yet unknown, and that the process of development was a progress from spell to prayer. On this theory, spells, in the course of time, and in accordance with their own law of growth, become prayers. The nature and operation of this law, it may be difficult or impossible now for us to observe. The process took place in the night of time and is therefore not open to our observation. But that the process, by which the one becomes the other, is a possible process, is perhaps shown by the fact that we can witness for ourselves prayer reverting or casting back to spell. Wherever prayers become 'vain repetitions,' it is obvious that they are conceived to act in the same way as the savage believes spells to act: the mere utterance of the formula has the same magical power, as making the sign of the cross, to avert supernatural danger. If prayers thus cast back to spells, it may reasonably be presumed that it is because prayer is in its origin but spell. It is because oxygen and hydrogen, combined, produce water, that water can be resolved into oxygen and hydrogen.